In particular "prices should converge" is hiding a pretty big precondition in very few words. You don't only need prices to converge, but you need them to conve

In particular "prices should converge" is hiding a pretty big precondition in very few words. You don't only need prices to converge, but you need them to converge within a reasonable time span, which is obviously not guaranteed. (because if the market was efficient already then the prices would have converged already and it would not be feasible to run arbitrages like this)